Circuit interrupter



May 26, 1925.

T. T. GREENWOOD CIRCUIT INTERRUPTER Filed Sept. 1, 1922 Potential May 26, i

I UNITED "STATES v 1,538,986- ra rla rr OFFICE.

rm '1'. cannivwoon, or rmrm'ron,

TION OI MASS CHUSETTS.

MASSACHUSETTS, ASSIGNOB, BY MERE AS- SIGNMENTS, '1O CONDIT ELECTRICAL MANUFACTURING COMPANY,

A CORPORA- CIBOUI'I. INTEBBUPTEB.

Application fllcd september 1, 1922. Serial No. 585,670.

To all whom it may concern;

.Be it known that I, TALMA TrGREeN- woon, a citizen of the United States, residing at Templeton, in the county of Worcester and State of Massachusetts, have 1nvented an Improvement in Circuit Interrupters, of which the following is a specification. I

This invention relates to electric switches, and especially to oil-immersed electric switches, adapted to carry currents of a.

relatively high value.

Electric switches having a high currentcarrying capacity are or may be of the inverted brush type wherein laminated or brush members are carried by the fixed switch studs and comprise the main stationary contact members of the switch, and a relatively massive bar may serve as the bridging member and is adapted to engage and electrically connect said fixed brush members, and comprises the movable switch member. I

With the usual'type of inverted brush construction, the brush member is bolted or otherwise secured to a face of the fixed switch stud. With this arrangement the. current in the upper laminae of the brush member must pass through the contact junctions between the laminae before passing into the switch stud. While the contact junction between the adjacent laminae may have a relatively low electrical resistance yet, due to the relatively large value of current, the heating of the brush member is excessive and reduces greatly the current-carrying capacity of the switch. It has been pro to braze or solder the laminae together in that portion of the brush member secured to the switch stud but this is undesirable by reason of expense, increased stiffness of the brush member and danger of weakening the lamina by overheating and, furthermore, may not give the expected increase in current-carrying capacity.

It is an object of this invention to provide a brush member and a, switch stud so arranged that each laminae of the brush member may make independent contact with the switch stud whereby the current in each laminae may pass directly to the switch stud without traversing other laminae of the brush member.

For this purpose the switch stud may have a reces adapted to receive the brush member andthe laminae of the brush member may have reflexed resilient portions adapted tobe forced yieldingly into en agement with the side walls of the recess w mmby to make electrical contact therewith.

The means, as bolts, by which the brush member is secured to the switch stud may also serve as the means to force the reflexed resilient portions of the brush member into engagement with the sidewalls of the recess of the switch stud.

A further object is generally to improve the construction and operation of electric switches. i

Fig. 1 is a front view of the elements of an electric switch embodying and associated with this invention.

Fig. 2 is a section along line 2-2 of Fig. 1..

Fi 3 is a perspective view of a lamina of a rush member.

Fig. 4: is a perspective view of an assembled brush member composed of laminae as illustrated in Fig. 3. I

As here shown my invention is applied to the electric switch having the stationary switch members including the fixed studs.

brush members 13, which latterconiprise the stationary main contact members of the switch. Stationary auxiliary contact members 14 of any desirable construction may also be carried by and connected electrically with said brush holders 12. The movable switch member may include the rod 15, which may be made of insulating material, and a bridging member, comprising a conducting bar 16, may be carried by the end of said rod and is adapted to be moved upwardly into contact with said main and auxiliary contact members, whereby to complete the circuit through the switch, and also downwardly to interrupt the circuit through the switch.

In accordance with the invention, the brush holder 12 is provided with a bottom wall 18 and side walls 19 which together form a recess between which the brush member is received and said side walls 19 are adapted to be of sufiicwnt e g h nd I able switch member. In accordance with this invention the shank portion 20 is provided, on one or both sides, with cars 22 which are struck upwardly and laterally outward at an angle with said shank portion. Said ears are adapted to be forced into engagement with the side Walls 19 of the brush holder and make electrical contact therewith and are adapted to have a suitable length to provide a suitable extent of contact with the side walls. Preferably the total length of the contact edges of .the ears of the lamina is substantially equal to the length of the contact edge of the toe portion 21 of the lamina.

The brush member is assembled with the laminae so disposed that the toe portions are directed downward and the ears are directed upward. The assembled brush member is received in the brush holder with the cars 22 directed toward the bottom wall 18 of the recess in the brush holder. The brush member is secured in the brush holder by suitable clamping means, as the bolts 25, which are or may be threaded in the brush holder and, preferably, a pressure plate 26 is interposed between the brush member and the heads of said bolts. Said clamping means is adapted to force the brush laminae toward the bottom wall 18 of the brushrecess. By so doing, the clamping means operates to spread the cars 22 of the brush laminae and cause them to flatten out and wedge against and imbed in the side walls 19 of the brush holder whereby to make good electrical contact therewith.

It is seen that, with this arrangement, each lamina of the brush member may be forced into independent electrical contact with the brush holder and that the current in each lamina may pass directly into the brush holder without traversing other laminae of the brush member.

The structure may be otherwise modified without departing from the spirit of the invention.

I claim:

1. In an electric switch, the combination of a brush holder having a recess, and a laminated brush member having the edges of the laminae thereof arranged in springcontact with the side walls of the recess of said brush-holder by their own spring-action.

2. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder arranged'in spring-pressed edgcwise contact with said brush holder by the inherent resiliency of said brush member.

3. In an electric switch, the combination of a brush holder, a brush member carried by said brush holder, and clamping means arranged to flex the edges of said brush member into contact with said brush holder.

4. In an electric switch, the combination of a. brush holder, and a brush member carried by said holder having reflexed portions arranged in edgcwise engagement with said brush holder.

5. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder said brush member comprising a plurality of laminic which are arranged in edgcwise spring contact with said brush holder by their own spring-action.

6. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder, said brush member comprising a plurality of laminae having reflexed edge-portions which are arranged in edgewise contact with said brush holder.

7. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder, said brush member comprising a plurality of laminae having reflexed edge-portions, and clamping means arranged to force said reflexed ed eportions into edgcwise pressure contact with said brush holder.

8. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder, said brush member comprising a plurality of laminae having their opposite side portions refiexed and arranged in edgcwise pressure contact with said brush holder.

9. In an electric switch, the combination of a brush holder, and a brush member carried by said brush holder, said brush member comprising a plurality of laminae having their opposite side portions reflcxed in the same direction, and clamping means arranged to force said reflexed portions into edgcwise contact with said brush holder.

10. In an electric switch, the combination of a brush holder having spaced side walls, a laminated brush member carried by said brush holder and disposed between said side walls, and clamping means to force and ex pand the laminae of said brush member into edgcwise contact with said side walls.

11. In an electric switch, the combination of a brush holder having spaced side walls, a laminated brush member carried by said brush holder and disposed between said side walls, and means to force and expand the laminae of said brush member laterally into edgewise contact with said side walls.

. 12. In an electric switch, the combination of a brush holder having a bottom wall and spaced side walls, and a brush member carried by said holder on the bottom wall thereof and having laminae formed with reflexed side-portions which are arranged in edgewise contact with the side walls of said brush holder.

13. In an electric switch, the combination of a. brush holder having a bottom wall and spaced side walls, and a brush member carried by said holder on the bottom wall thereof and having laminae formed with reflcxed side-portions which are arranged in edgewise contact with the side walls of said brush holder, and means to force and hold said laminae in such edgewise contact with said brush holder.

14. In an electric switch, the combination of a brush holder, a brush member carried by said brush holder, said brush member having lamina: formed with independent resilient portions, and means to force said resilient portions of said laminae into edgewisc contact with said brush holder.

15. In an electric switch, the combination of a brush holder having a bottom wall and spaced side walls, a brush member carried by said holder on the bottom wall and between the side walls thereof. said brush member having lamina: formed with reflexed lateral portions, and clamping means carried by said brush holder arranged to force the reflexed lateral portions of the laminae of said brush member into edgewise con-tact with theside walls of said holder.

16. In an electric switch, the combination of a brush holder having a bottom wall and spaced side walls, a brush member carried by said holder on the bottom wall and between the side walls thereof. said brush member having laminae formed with reflexed lateral portions, and clamping means including bolts passed through said brush member and threaded in said brush. holder and a pressure plate disposed between said bolts and the brush member arranged to force the reflexed lateral portion of the lamiuse of said brush member into edgewise contact with the side walls of said holder.

17. In an electric switch, the combination of a brush holder and a laminated brush member carried by said holder and means associated with said brush member arranged to establish. electrical connection between the independent laminae of the brush and the brush holder.

In testimony'whereof, I have signed my 

